1. Field of the Invention
The present invention relates to a polycrystalline structure film often utilized in a magnetic recording medium such as a hard disk (HD), for example.
2. Description of the Prior Art
Texture is well known in the technical field of hard disks. The texture is normally established over the surface of an aluminum substrate, for example. Abasement layer and a magnetic layer for recordation made of a crystalline layer are layered on the surface of the substrate. The texture serves to establish the magnetic anisotropy in the circumferential direction of the substrate in the magnetic layer for recordation. The magnetic characteristic is thus improved in the hard disk.
A glass substrate is recently utilized in the hard disk in place of the aluminum substrate. Texture is hardly formed over the surface of the hard glass substrate. The magnetic anisotropy should be established in the magnetic layer on the glass substrate without the texture. Japanese Patent Application Publication No. 2002-203312 proposes a technique to form an inclined growth crystalline layer. Individual crystal grains grow in a direction inclined from the orthogonal direction perpendicular to the surface of the substrate in the inclined growth crystalline layer, for example. A crystalline layer is formed on the inclined growth crystalline layer. The inclined growth crystalline layer serves to improve the magnetic anisotropy in the circumferential direction in the crystalline layer.